1. Field of the Invention
This invention relates to the formation of crystalline co-polybenzyls. In particular, this invention relates to the copolymerization of 2,5-dimethylbenzyl halide with another alkyl ring-substituted benzyl halide of the same series in the presence of a Ziegler-type catalyst. The invention further relates to the process of polymerizing benzyl halides to highly crystalline co-polybenzyl halides.
2. Description of the Prior Art
The condensation polymerization of benzyl halides as well as alkyl ring-substituted benzyl halides with acidic catalysts is well known in the art. Prior methods for the formation of polybenzyls have involved the use of Friedel-Crafts catalysts. Polybenzyls formed with Friedel-Crafts catalysts, as reported in U.S. Pat. No. 2,241,488 and in the literature, H. C. Haas et al, J. Poly. Sci., XV, 503 (1955), tend to be resinous solids having softening points over the range of about 75.degree. to 80.degree. C. and melting at about 95.degree. C. In addition to the use of classical Friedel-Crafts catalysts, polybenzyls have been prepared with various types of alkyl-metal compounds, see, for example, Chemical Abstracts 59, 7661a (1963) and 57, 15338c (1962).
In U.S. Pat. No. 3,418,259 of Kennedy et al, issued Dec. 24, 1968 there is disclosed a method of polymerizing crystalline homopolybenzyls in the presence of Friedel-Crafts catalysts and for the preparation of amorphous copolymers of benzyl halides and a C.sub.3 -C.sub.8 .alpha.-monoolefin.
In U.S. Pat. No. 3,346,514 of Isaacson et al issued Oct. 10, 1967 there is disclosed a method of polymerizing crystalline homopolybenzyls in the presence of a Ziegler-type catalyst. Heretofore crystalline copolybenzyls have not been known.